VO2 MAX
SCORES.

Wearables: Garmin, Apple Watch, Whoop, and Polar all estimate VO2 max automatically from heart rate data during runs. Open your fitness app and look for "cardio fitness" or "VO2 max."

Cooper Test: No wearable? Run as far as you can in exactly 12 minutes on flat ground. Use a standard Cooper Test calculator to convert your distance to an estimated VO2 max.

Zone 2 training is the foundation — 2–3 sessions per week of sustained effort where you can hold a full conversation (roughly 60–70% of max heart rate). This builds the aerobic base.

High-intensity intervals push the ceiling faster — one hard session per week alongside Zone 2 is enough. Men in their 40s and 50s have shown 15–20% VO2 max improvements in focused 6-month training blocks.

The average sedentary man in his 40s sits in the low-to-mid 30s. Peter Attia, longevity researcher and physician, calls VO2 max "probably the single most powerful predictor of longevity we have."

For men 40–49, a realistic target is 39–45+ — Good to Excellent range. Getting from Very Poor to Average is associated with a 50% reduction in all-cause mortality risk.

VO2 max drops roughly 1% per year from your 30s without training intervention — driven by declining cardiac output, reduced muscle mitochondrial density, and lower haemoglobin levels.

Consistent aerobic training can slow this significantly. A fit 50-year-old can have a higher VO2 max than a sedentary 35-year-old. The number is not fixed — it responds to training at any age.